<!doctype html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport"
        content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>MVC</title>
</head>
<body>
<div id="page">
  <section id="app1">
    <div class="output">
      <span id="num">100</span>
    </div>
    <div class="actions">
      <button id="add">+1</button>
      <button id="sub">-1</button>
      <button id="mul">*2</button>
      <button id="div">/2</button>
    </div>
  </section>
  <section id="app2">
    <ul class="tab-bar">
      <li>tab11111</li>
      <li>tab22222</li>
    </ul>
    <ul class="tab-content">
      <li>内容1</li>
      <li>内容2</li>
    </ul>
  </section>
  <section id="app3">
    <div class="square"></div>
  </section>
  <section id="app4">
    <div class="circle"></div>
  </section>
</div>
</body>
<script src="main.js"></script>
</html>